llvm-readobj: Try the DWARF CFI dumper on all machines.

[pcc]

Summary

There's no reason to limit the DWARF CFI dumper to EM_386 and EM_X86_64;
ELF files could contain DWARF CFI on almost any platform (even 32-bit ARM;
NetBSD uses DWARF CFI on that platform). So start using the DWARF CFI dumper
unconditionally so that we can dump .eh_frame sections on the remaining ELF
platforms as well as in NetBSD binaries.

[efriedma]

LGTM

I had a very similar change in my tree recently to debug an issue with unwinding on AArch64.

llvm/test/tools/llvm-readobj/arm-dwarf-cfi.s

+# RUN: llvm-mc -triple arm-linux -filetype obj -o - %s | llvm-readobj -u | FileCheck %s
+
+# CHECK:      [0x0] CIE length=16
+# CHECK-NEXT:   version: 1
+# CHECK-NEXT:   augmentation: zR
+# CHECK-NEXT:   code_alignment_factor: 1
+# CHECK-NEXT:   data_alignment_factor: -4
+# CHECK-NEXT:   return_address_register: 14
+
+# CHECK:        Program:
+# CHECK-NEXT: DW_CFA_def_cfa: reg13 +0
+
+# CHECK:      [0x14] FDE length=16 cie=[0x0]
+# CHECK-NEXT:   initial_location: 0x0
+# CHECK-NEXT:   address_range: 0x4 (end : 0x4)
+
+# CHECK:        Program:
+# CHECK-NEXT: DW_CFA_nop:
+# CHECK-NEXT: DW_CFA_nop:
+# CHECK-NEXT: DW_CFA_nop:
+
+.cpu cortex-a8
+
+foo:
+.cfi_startproc
+bx lr
+.cfi_endproc

llvm/test/tools/llvm-readobj/arm64-dwarf-cfi.s

+# RUN: llvm-mc -triple arm64-linux -filetype obj -o - %s | llvm-readobj -u | FileCheck %s
+
+# CHECK:      [0x0] CIE length=16
+# CHECK-NEXT:   version: 1
+# CHECK-NEXT:   augmentation: zR
+# CHECK-NEXT:   code_alignment_factor: 1
+# CHECK-NEXT:   data_alignment_factor: -4
+# CHECK-NEXT:   return_address_register: 30
+
+# CHECK:        Program:
+# CHECK-NEXT: DW_CFA_def_cfa: reg31 +0
+
+# CHECK:      [0x14] FDE length=16 cie=[0x0]
+# CHECK-NEXT:   initial_location: 0x0
+# CHECK-NEXT:   address_range: 0x4 (end : 0x4)
+
+# CHECK:        Program:
+# CHECK-NEXT: DW_CFA_nop:
+# CHECK-NEXT: DW_CFA_nop:
+# CHECK-NEXT: DW_CFA_nop:
+
+foo:
+.cfi_startproc
+ret
+.cfi_endproc

llvm/tools/llvm-readobj/ELFDumper.cpp

void ELFDumper<ELFT>::printValue(uint64_t Type, uint64_t Value) {
   default:
     OS << format(ConvChar, Value);
     break;
   }
 }
 
 template<class ELFT>
 void ELFDumper<ELFT>::printUnwindInfo() {
-  const unsigned Machine = ObjF->getELFFile()->getHeader()->e_machine;
-  if (Machine == EM_386 || Machine == EM_X86_64) {
-    DwarfCFIEH::PrinterContext<ELFT> Ctx(W, ObjF);
-    return Ctx.printUnwindInformation();
-  }
-  W.startLine() << "UnwindInfo not implemented.\n";
+  Ctx.printUnwindInformation();
 }
 
 namespace {
 
 template <> void ELFDumper<ELF32LE>::printUnwindInfo() {
   const ELFFile<ELF32LE> *Obj = ObjF->getELFFile();
   const unsigned Machine = Obj->getHeader()->e_machine;
   if (Machine == EM_ARM) {
     ARM::EHABI::PrinterContext<ELF32LE> Ctx(W, Obj, DotSymtabSec);
-    return Ctx.PrintUnwindInformation();
+    Ctx.PrintUnwindInformation();
   }
-  W.startLine() << "UnwindInfo not implemented.\n";
+  DwarfCFIEH::PrinterContext<ELF32LE> Ctx(W, ObjF);
+  Ctx.printUnwindInformation();
 }
 
 } // end anonymous namespace
 
 template<class ELFT>
 void ELFDumper<ELFT>::printDynamicTable() {
   auto I = dynamic_table().begin();
   auto E = dynamic_table().end();